Neurogene Reports Positive Long-Term Phase 1/2 Data For Rett Syndrome Gene Therapy

(RTTNews) - Neurogene Inc. (NGNE) on Monday reported positive long-term data from its Phase 1/2 study of NGN-401 in females with Rett syndrome, a rare neurological disorder that primarily affects girls.

Across 10 participants, the therapy led to the gain of 47 developmental milestones, averaging 4.7 milestones per patient. All participants improved on the Clinical Global Impression-Improvement (CGI-I) scale and gained at least one developmental milestone, with benefits continuing through up to 30 months of follow-up and no loss of milestones reported.

The company said participants showed progressive improvements across key Rett syndrome measures, with a median time to first clinical improvement of two months after treatment.

NGN-401 continued to be generally well tolerated, with no treatment-related serious adverse events or dose-limiting toxicities reported in the Embolden registrational trial as of June 16, 2026.

Neurogene shares were up more than 1% in pre-market trading after closing at $32.03 on Friday.